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The general form of the model equation is E{μ} = f(X ₁, X ₂, … , β ₀, β ₁, …) where f() stands for some algebraic expression. For modeling one has to choose some specific f() and the question was how to do so. Even if the right f() is not known one can still make decent estimates of E{μ}. However, to say what change in E{μ} is caused by a some change in a predictor variable, not knowing the right f() can be a problem. The task of fashioning the f() out of predictor variables and parameters is difficult. Road safety data can be represented by many different and footloose functions, and what the modeler chooses matters in terms of what estimates are produced. Limited guidance is offered.